CN104874612A - Hundred-meter-rail double-arc reverse pre-bending process - Google Patents

Abstract

The invention discloses a hundred-meter-rail double-arc reverse pre-bending process, and belongs to the technical field of steel rail rolling production. The process comprises reverse pre-bending curve parameter setting and pre-bending vehicle use scheme design steps, wherein the proportion of the length of a linear segment to the length of a bent section of a steel rail is set to be 0.6-1.5; the total height of reverse bend is 1.5-2.8 m, the temperature of the reverse bend is 750-820 DEG C; the change rate of the slope of the bent section is set according to the following formula: dy''=-(R2-x2)-1/2-x2(R2-x2)-3/2, wherein dy'' is the change rate of the slope; R is the curvature radius of the circular arc of the bent segment; x is the coordinate of the curve position; the use scheme of pre-bending vehicles is that the pre-bending vehicles are arranged at an equal interval of 1.6 m at the bent segment to perform reverse bending of the steel rail and the pre-bending vehicles are arranged at an equal interval of 3.2 m at the linear segment. The process is applied to a steel rail cooling and reverse pre-bending process, so the maximum chord height of bend after cooling of hundred-meter-rail is controlled to be 40-60 mm, the straightness of the steel rail is greatly improved, and a foundation is laid for successfully straightening the steel rail with qualified flatness.

Description

Hundred meters of two reverse prebending process of arc of rail

Technical field

The present invention relates to the two reverse prebending process of arc of hundred meters of rail, belong to steel rail rolling production technical field.

Background technology

Rail is the symmetrical and asymmetric compound section product of x-axis of y-axis, rolling rear rail is be poured on cold bed naturally to cool, temperature about needs 3 hours by 800 DEG C of cool to room temperature, experiencing variations in temperature and tissue change, after cooling, rail bends towards rail head, defines cold rear flexibility, and the rail cooled down like this bends to rail head, action, more than 3.5 meters, causes hundred meters of rail can not enter next procedure smoothly.For reducing by hundred meters of cold rear flexibility of rail, the method generally adopted in the industry is: measure rail not through the cooled buckling curve of pre-bending, then apply equivalent bending to the flange of rail, realize the aligning to deflection of rail; But, due to rail cold after degree of crook be subject to the many factors such as pre-bending temperature, material, rail type, cold bed coefficient of friction, cooldown rate, pre-bending curve form, control difficulty larger, the rear rail of practice measurement cooling very easily forms " W " type and bends, and state labile, still can not meet high straightness hundred meters of rail requirements.

Summary of the invention

Technical problem to be solved by this invention is to provide the two reverse prebending process of arc of a kind of hundred meters of rail, by setting up reverse pre-bending parameter of curve, pre-bending car action scheme is set, thus largest chord is high to be controlled at 40-60mm to make hundred meters of rail coolings bend afterwards, significantly improve steel rail straightness, under effect of weight, enter next procedure smoothly with micro-form of sticking up after rail turnover, solve the defect in background technology.

The technical scheme solved the problems of the technologies described above is:

Hundred meters of two reverse prebending process of arc of rail, comprise reverse pre-bending curve Parameter setting step and pre-bending car operational version design procedure; Described reverse pre-bending curve Parameter setting step comprises rail straight line section and bending section ratio sets, recurvation height overall sets, recurvation temperature sets and bending section slope variation rate setting; Rail straight line segment length and bending section length ratio are set to 0.6 ~ 1.5, recurvation height overall 1.5 ~ 2.8m, and recurvation temperature is 750 DEG C-820 DEG C, and bending section slope variation speed sets according to the following equation:

dy″＝-(R ²-x ²) ^-1/2-x ²(R ²-x ²) ^-3/2；

Wherein: dy 〞---to slope variation speed;

R---bending section circular arc radius of curvature;

X---curve location coordinate;

Described pre-bending car carries out back-flexing with spaced set to rail at bending section according to pre-bending parameter of curve, carries out equidistant constant speed movement at straightway with spaced set.

The two reverse prebending process of arc of hundred meters of above-mentioned rail, described straightway is positioned in the middle part of rail, and described bending section is 2, lay respectively at the both sides of straightway, each bending section comprises bending one section and bending two sections, and bending one section of one end is tangent with straightway one end, and the other end is with to bend two sections tangent; A bending slope over 10 rate of change is set as 0.4% ~ 0.6%, and bending two slope over 10 rate of changes are set as 0.6% ~ 0.8%.

The two reverse prebending process of arc of hundred meters of above-mentioned rail, described rail straight line segment length is 40 ~ 60 meters, and each bending section length is 20 ~ 30 meters; Bending one section of radius of curvature is set as 180m ~ 250m, and bending two sections of radius of curvature are set as 120m ~ 170m.

The two reverse prebending process of arc of hundred meters of above-mentioned rail, described distance between the adjacent pre-bending car of bending section is 1.6 meters or 3.2 meters, distance between the adjacent pre-bending car of straightway is 3.2 meters or 4.8 meters, and pre-bending dolly uses total amount to be 42 ~ 50 groups, and pre-bending dolly stroke function is:

$f\left(x\right)=93.87+2.57x+2.957x^2+0.1222x^3+(0.68+0.0004t)x+\frac{1}{2}\mathrm{kx}$

Wherein: f (x)---pre-bending dolly stroke;

X---dolly sequence number;

T---recurvation temperature

K---rail profile coefficient.

Pre-bending curve setting parameter of the present invention is according to being: because rail straight line section and bending section ratio need to consider whether rolled piece produces reverse resilience in motion process with after dynamic (quiet) beam point cantact on cold bed, and straightway and bending section ratio are set to 0.6 ~ 1.5 by the rail specificity analysis through great many of experiments and the condition of high temperature; Temperature and the product section of recurvation height overall and recurvation are relevant, and production practices prove, along with the reduction of temperature, the total a large amount of recurvation reduces, temperature 750 DEG C-820 DEG C when controlling recurvation in production, and now returning curved height overall, to be set to 1.5 ~ 2.8m comparatively reasonable; Bending section slope variation speed refers to bending section curve second dervative, and its setting is relevant with location of rail, and larger rate of change is got in the position close to both sides, and less rate of change is got in the position close to middle part, can obtain formula by arranging:

dy″＝-(R ²-x ²) ^-1/2-x ²(R ²-x ²) ^-3/2，

Wherein: dy 〞---to slope variation speed;

R---bending section circular arc radius of curvature;

X---curve location coordinate;

A bending slope over 10 rate of change value 0.6% ~ 0.8% is summed up, bending two slope over 10 rate of change value 0.4%-0.6% by great many of experiments; Pre-bending car operational version is determined to be directly proportional to bending section length, so give rail back-flexing at bending section with 1.6 meters of spaced set pre-bending cars, flat segments is with 3.2 meters of equidistant constant speed movement of spaced set pre-bending car; By hundred meters of rail reverse pre-bending experimental data Modling model, return out pre-bending dolly stroke function:

$f\left(x\right)=93.87+2.57x+2.957x^2+0.1222x^3+(0.68+0.0004t)x+\frac{1}{2}\mathrm{kx}$

Wherein: f (x)-pre-bending dolly stroke

X-dolly sequence number

T-pre-bending temperature

K-rail profile coefficient (relevant to rail specification).

Beneficial outcomes of the present invention is:

The present invention is applied to rail and cools in reverse pre-bending process, make whole cold rear rail residual deformation close to level, it is bending after the cooling of hundred meters of rail that largest chord is high controls at 40-60mm, significantly improve steel rail straightness, overturn backward micro-ly to stick up simultaneously, for the follow-up rail successfully aligning out hundred meters of glacing flatness qualified is laid a good foundation, there are significant economic benefit and social benefit.

Accompanying drawing explanation

Fig. 1 is the reverse prebuckling line chart designed by this patent;

Fig. 2 is bending section composition diagram;

In figure, mark is as follows: straightway 1, bending section 2, recurvation height overall 3, bending one section 4, bend two section 5.

Detailed description of the invention

Fig. 1 and Fig. 2 shows, the straightway 1 be positioned in the middle part of rail and two bending sections 2 laying respectively at straightway 1 both sides are comprised when rail cools on cold bed, each bending section 2 comprises bending one section 4 and bending two section 5, one end of bending one section 4 is tangent with straightway 1 one end, and the other end is with to bend two section 5 tangent; The two reverse prebending process of arc of the present invention's hundred meters of rail, comprises reverse pre-bending curve Parameter setting step and pre-bending car operational version design procedure; Reverse pre-bending curve Parameter setting step comprises that rail straight line section 1 sets with the ratio of bending section 2, the setting of recurvation height overall 3, recurvation temperature set and bending section slope variation rate setting; Because rail straight line section 1 and the ratio of bending section 2 need to consider whether rolled piece produces reverse resilience in motion process with after dynamic (quiet) beam point cantact on cold bed, straightway 1 and the ratio of each bending section 2 are set to 0.6 ~ 1.5 by the rail specificity analysis through great many of experiments and the condition of high temperature, the length of straightway 1 is 40 ~ 60 meters, and the length of each bending section 2 is 20 ~ 30 meters; Temperature and the product section of recurvation height overall 3 and recurvation are relevant, and production practices prove, along with the reduction of temperature, the total a large amount of recurvation reduces, and temperature 750 DEG C-820 DEG C when controlling recurvation in production, now returns curved height overall and be set to 1.5 ~ 2.8m; Bending section slope variation speed refers to bending section curve second dervative, and its setting is relevant with location of rail, and larger rate of change is got in the position close to both sides, and less rate of change is got in the position close to middle part, can obtain formula by arranging:

dy″＝-(R ²-x ²) ^-1/2-x ²(R ²-x ²) ^-3/2；

Wherein: dy 〞---to slope variation speed;

R---bending section circular arc radius of curvature;

X---curve location coordinate;

Summed up the slope variation speed value 0.6% ~ 0.8% of bending a section 4 by great many of experiments, radius of curvature is set as 180 ~ 250 meters, the slope variation speed value 0.4%-0.6% of bending two section 5, and radius of curvature is set as 120 ~ 170 meters; Pre-bending car operational version is determined to be directly proportional to the length of bending section 2, so give rail back-flexing at bending section with 1.6 meters of spaced set pre-bending cars, flat segments is with 3.2 meters of equidistant constant speed movement of spaced set pre-bending car; Pre-bending dolly 6 uses total amount 42 ~ 50 groups; By hundred meters of rail reverse pre-bending experimental data Modling model, return out pre-bending dolly stroke function:

$f\left(x\right)=93.87+2.57x+2.957x^2+0.1222x^3+(0.68+0.0004t)x+\frac{1}{2}\mathrm{kx}$

Wherein: f (x)---pre-bending dolly stroke;

X---dolly sequence number;

T---recurvation temperature

K---rail profile coefficient.

Pre-bending dolly stroke bilateral symmetry, therefore only calculates a side data and can determine opposite side parameter value.

The present invention adopts bending one section of 4 radius of curvature and bending two section of 5 radius of curvature tangent and forms two arc transition, the diverse location slope variation speed realizing rail is different, form smoothed curve, enforcement of the present invention be by pre-bending dolly in high-temperature region by the track transverse shifting of rail by reverse pre-bending curve, the speed of service of each pre-bending dolly is relevant to the coordinate of setting, and last moment each pre-bending dolly reaches reverse pre-bending curve desired location simultaneously.

Have employed following 4 kinds of embodiments in production scene, concrete condition is described as follows:

Claims (4)

1. hundred meters of two reverse prebending process of arc of rail, is characterized in that: comprise reverse pre-bending curve Parameter setting step and pre-bending car operational version design procedure; Described reverse pre-bending curve Parameter setting step comprises that rail straight line section (1) and bending section (2) ratio set, the setting of recurvation height overall (3), recurvation temperature sets and the slope variation rate setting of bending section (2); Rail straight line section (1) length and bending section (2) length ratio are set to 0.6 ~ 1.5, recurvation height overall (3) is set to 1.5 ~ 2.8m, recurvation temperature is 750 DEG C-820 DEG C, and the slope variation speed of bending section (2) sets according to the following equation:

dy″＝-(R ²-x ²) ^-1/2-x ²(R ²-x ²) ^-3/2；

Wherein: dy 〞---to slope variation speed;

R---bending section circular arc radius of curvature;

X---curve location coordinate;

Described pre-bending car carries out back-flexing with spaced set to rail at bending section (2) according to pre-bending parameter of curve, carries out equidistant constant speed movement at straightway (1) with spaced set.

2. as claimed in claim 1 hundred meters of two reverse prebending process of arc of rail, it is characterized in that: described straightway (1) is positioned in the middle part of rail, described bending section (2) is 2, lay respectively at the both sides of straightway (1), each bending section comprises bending one section (4) and bending two sections (5), bending one section of (4) one end is tangent with straightway (1) one end, and the other end is with to bend two sections (5) tangent; The slope variation rate setting of bending one section (4) is 0.4% ~ 0.6%, and the slope variation rate setting of bending two sections (5) is 0.6% ~ 0.8%.

3. as claimed in claim 1 or 2 hundred meters of two reverse prebending process of arc of rail, is characterized in that: described rail straight line section (1) length is 40 ~ 60 meters, and each bending section (2) length is 20 ~ 30 meters; Bending one section of (4) radius of curvature is set as 180m ~ 250m, and bending two sections of (5) radius of curvature are set as 120m ~ 170m.

4. as claimed in claim 1 or 2 hundred meters of two reverse prebending process of arc of rail, it is characterized in that: described distance between the adjacent pre-bending car of bending section (2) is 1.6 meters or 3.2 meters, distance between the adjacent pre-bending car of straightway (1) is 3.2 meters or 4.8 meters, pre-bending dolly uses total amount to be 42 ~ 50 groups, and pre-bending dolly stroke function is:

$f\left(x\right)=93.87+2.57x+2.957x^2+0.1222x^3+(0.68+0.0004t)x+\frac{1}{2}\mathrm{kx}$

Wherein: f (x)---pre-bending dolly stroke;

X---dolly sequence number;

T---recurvation temperature

K---rail profile coefficient.